It is optional?! Isn't it the default when using crypto libraries?
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H MApr 28 '13 at 6:14

No, ..., which is why I found the last part of your post strange. $\:$
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Ricky DemerApr 28 '13 at 6:18

@Ricky Demer, I think it is considered an important weakness in a cipher that an adversary can discover such thing from the ciphertext, so I guessed it should be somehow prevented by default (but i were not sure so I posted a question about it).
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H MApr 28 '13 at 6:34

1 Answer
1

The answer to your question is "yes, RSA will encrypt the same cleartext to the same ciphertext every time." And yes, this is a known property of RSA. That's why every standard that uses RSA, such as PKCS or CMS, specifies the use of randomized padding.